Japan Reconnaissance - Wrap Up
Posted on May 25 2011
This will be my last post for this reconnaissance trip. I had a smooth return trip – all flights on time! On my last day in Tokyo, I met with Professor Tsuji of the University of Tokyo. Tsuji-sensei is well-known in tsunami science – having participated in or lead post-tsunami field investigations all over the world. His keen eye, breadth of background, and infectious humor have helped to create the International Tsunami Survey Team (ITST) format that we use today. He is also known for having found the highest inundation in the 1993 Okushiri tsunami (over 90 feet), and the second highest point in the current tsunami (over 120 feet). He is a very busy man, the phone constantly ringing with inquiries from the media, government officials, and other scientists. I was lucky to have an hour appointment. He’s seen much more of the inundation area than I have. I was particularly interested in the story of the town of Taro in Iwate Prefecture. Taro was famous for the Japanese “Great Wall of China “ a towering 33-foot edifice that was completed in 1958 to protect the town from tsunamis. When new development began outside the limits of the older walls, a new was extended in the 1990s to cover this area also. Unfortunately, the construction company who built the new wall failed to put in steel or other reinforcement to hold sections of the wall together and the tsunami toppled them as easily as child’s blocks. The tsunami was high enough to overtop the old walls as well, but they didn’t topple and the level of damage in the older area was a little less. The standing walls did reduce the amount of flooding and gave residents an extra few minutes to get to higher ground. More on Taro Here.
I asked him about how Japan should be approaching tsunami hazard mitigation issues in the future. He suggested a two-tier approach. Tsunamis are much more frequent in Japan than on the West Coast of the United States. Major tsunamis occurred in 1896, 1933 and 1960. Sea walls and engineered tsunami abatement structures should still be the primary line of defense for these relatively common tsunamis. But there needs to be a second tier – a life safety plan to protect people from much larger tsunamis such as the March 11 event. This is what needs to worked on and applied to other tsunami prone areas as well as the NE coast of Honshu.
I’m still sorting through my notes and photographs to summarize our findings from the trip. I took more than 1200 photos and Megumi has a similar number. A small sampling is posted Here.
We conducted more than 30 detailed interviews. I am also pouring through the reports from other scientific teams and the flood of government and other reports that have been released. Here are my preliminary thoughts on the themes that are emerging. My disclaimer is that “preliminary” is the operative word here. Additional information may change some of these findings.
The most important lesson is that underestimating the hazard has tragic consequences.
Japan spends more of their GDP on earthquake and tsunami hazard mitigation than any other country in the world. This includes more instruments, more tsunami scientists and engineers, more numerical modeling, and more engineering works. These mitigation efforts were built on an assessment of the size of the likely maximum earthquake and maximum tsunami that turned out to be wrong. The majority of sea walls in the affected area (like those in Taro) built to restrain the tsunami and many of the designated vertical evacuation places were overtopped or failed in the event. Because it was expected that the mitigation efforts would be effective, there was no catastrophic response plan in place. This affected the ability to effectively respond, to coordinate both national and international offers of assistance, and prolonged the amount of time some people were on their own in isolated evacuation places.
There had been a few studies by geologists that suggested a much greater hazard than had been adopted in planning efforts and it is easy now to point back at those studies and say they should have been used. Hazard assessment is a difficult process, the historic record (even in Japan) is short and interpreting paleoseismic data is not always straightforward. Megathrust earthquakes (earthquakes with magnitudes of 8.5 and greater) are particularly tricky because they are so rare. Sixteen magnitude 8.5 or larger earthquakes have been recorded on seismographs (post 1900), and only five of these were magnitude 9 or larger. Both 9+ earthquakes that have occurred since modern broadband instruments have been in existence have changed the conventional wisdom. The 2004 Andaman Sumatra earthquake changed our ideas about the relationship among earthquake size, age of crustal material, and convergence rate, and the Japan earthquake is challenging the accepted scientific ideas about the relationship among magnitude, fault area, and slip.
I have been privileged to work with and learn from many of Japan’s earthquake/tsunami professionals for years and as a group they are an extremely hard working and conscientious and this earthquake showed that much of their effort was successful. On first look, it appears that the built environment performed very well even when subjected to some of the strongest ground shaking levels ever recorded. The early warning system that analyzes an earthquake during the initial seconds of the rupture appears to have worked in shutting down trains and other facilities before the strongest shaking. While power went out at 2:46 PM when the earthquake struck, sirens, cell phones and radios continued to work in all of the areas we visited. In Chile, after the February 2010 M 8.8 earthquake, only one radio station continued to work in the Bio Bio region and cell phone coverage was down. In recent much smaller California earthquakes (2008 M 5.5 Chino Hills, 2010 M 7.2 Baja) both cell and landline telephone communications were jammed by overuse. But all of the successes in reducing earthquake impacts are overwhelmed by the enormity of the tsunami losses.
What I am taking away from Japan is the importance of allowing for uncertainty in hazard estimation and making sure we are conservative when it comes to life-safety decisions. We’ll be taking a long second look at what we have been doing in California – and I know that other folks working in the Cascadia region will be doing the same.
Here’s a quick take on other lessons (in no priority order)
• People not aware of risk. Few of the people we talked to thought they were at risk where they lived or worked. We don’t know the reasons for this – whether they believed the sea walls would protect them, or education efforts weren’t effective, or there were other reasons. I hope other groups study this issue in more detail.
• Vulnerability was a function of the unique geography of a location and the characteristics of the tsunami (height, flow velocities, duration, and arrival time). The situation on the broad coastal plain near Sendai was very different than the population centers like Minami Sanriku and Kesennuma that were built on alluvial flood planes and valleys near the mouths of large rivers. At East Matsushima, the situation was complicated by exposure from the ocean, a large river, a canal, and Matsushima Bay.
• Elderly appear to have been more vulnerable.
• Evacuation issues
People relied on cars
Planning centered on vertical evacuation in designated structures, rather than getting to high ground outside of the hazard area.
The earthquake often triggered behavior – but not to evacuate to a safe area. A number of people who were in safe areas, drove back to into hazardous areas after feeling the earthquake. Most often the reason was to check on/rescue loved ones at home, but in some cases it was to retrieve property.
Evacuation places were unprepared to hold people for days in winter conditions
Enormous shelter needs and inadequate shelter facilities – frustration of people in shelters with lack of privacy, bathing facilities, and lack of information about what is happening in their home towns.
Enormous temporary housing needs
Long duration loss of utilities and services in the affected area requiring resources – such as an army of traffic control officers at major intersections now without traffic signals
Relentless reminders of the event Aftershocks News/media coverage – daily revised body/missing counts, radiation levels
Reconstruction debates – how to rebuild and mitigate hazards from future tsunamis
• Loss of confidence in technical community
• The patience and perseverance and kindness of the people affected – lack of looting, cooperation, and general willingness to talk to us!
Japan Reconnaissance - Day -10
Posted on May 09 2011
May 9, 2011
We start out today with a short meeting with members of the International Tsunami Survey Team (ITST). This group is focused on tsunami deposits and tsunami geology. The challenge has been to find good transects that have been undisturbed by cleanup activity. We also meet with Masahiro Yamamoto, the Senior Advisor to the Intergovernmental Oceanographic Commission of UNESCO. I’m currently on the advisory team that Masahiro heads to revise the ITST post event survey guide. The first ITST guide was completed in 1998 and focused primarily and getting water height measurements. A lot has changed in the tsunami field since 1998 – technology and tools, scope, and involvement of many more disciplines. The revisions was supposed to be completed and ready for review by the end of March – one more thing the Japan tsunami postponed.
Then it’s back to Tokyo on the Shinkansen. It’s a clear day and everything looks normal from the window of the train. We discuss report strategies and next steps. One of the biggest challenges I have found in post event reconnaissance is distilling the information and getting reports written in a timely way. As soon as I returned, I’ll be inundated by all the work that has piled up over the past ten days, plus the items that were overdue before I left. I want to get a draft report done today while everything is still fresh in my mind and I still understand what my field notes refer to.
Japan Reconnaissance - Day -9
Posted on May 09 2011
May 8, 2011
A 5.7 to start the day and a 4.6 to go to bed by. They get one’s attention and are a frequent reminder that this event isn’t over yet. A few final tasks today in Iwate Prefecture before heading back to Sendai. We needed to track down the location of the shelters for people from Kessenuma and Minami Sanriku so we could get a comparison to the stories and experiences of the Sendai area. We are lucky today. It’s Sunday and we were concerned that city offices would be closed. But the man who ran the shelter last night was just clocking out to go home and is willing to guide us to the Ichinoseki temporary housing. After a long day and night’s work, this was really going out of his way for us. No matter what country I’ve been in, I’m always impressed and gratified by the kindness of strangers – especially the closer one gets to the disaster area. I’ve had some unpleasant hurdles set by a few bureaucrats far from the scene, but very few doors shut in my face in the midst of the destruction.
The Ichinoseki temporary housing facility makes use of partially occupied four-story public apartment buildings. We don’t feel comfortable knocking on doors so wait in the parking area hoping to intercept someone willing to talk to us as they enter or leave. It’s not a statistically accurate sampling technique, but at this point we are trying to be as unobtrusive as possible and still get an idea of the principal issues. We talk to two older men who were both outside of the inundation area when the earthquake struck and both headed back into the zone on feeling the earthquake. The first was from Kessenuma. He was at work away from the coast, and the earthquake was the trigger for him to get in his car and drive to his home. His wife was there and had mobility issues. He knew his house was at risk – it was in a low area near the river and frequently flooded. But he was stopped by the first tsunami surges before he was able to get home and he was able to turn around and drive to a safe area. Fortunately another relative had picked up his wife so they both survived. He spent 40 days in an evacuation shelter before moving into the temporary housing. Every day he goes back to Kessenuma to get information about the cleanup and recovery efforts because he gets no information where he now lives. The second man was from Minami Sanriku and he was working in his fields far from the coast when the earthquake struck. He had a different reason for wanting to go back to his house. He wanted to get his wallet and other personal belongings. His wife and daughter begged him not to go, but he went anyway. He was also stopped by the first tsunami surges before he arrived, and by driving very fast, was able to escape. We have heard this story now too many times – the earthquake was a trigger. Not the trigger to head to higher ground, but to go from a safe area and drive back into a hazard zone to get a loved one or to rescue possessions. We’ve only talked to the ones who escaped. My guess is that many of the victims did the same thing – they just weren’t as lucky.
On the drive back to Sendai, we pass close to Hiraizumi, and a good excuse to visit Chuson-ji, a famous Buddhist temple founded around 1100 by the Fujiwara clan. The first Fujiwara lord lost most of his family in the vicious civil wars of the era and established the temple to foster peace and reconciliation. It is a beautiful site – tall trees, a complex of beautifully restored temples and an opportunity to decompress and reflect on what we are learning. The site is one of two in Japan currently under consideration for World Heritage designation by UNESCO.
Japan Reconnaissance - Day -8
Posted on May 07 2011
May 7, 2011
How does one describe scenes of devastation day after day in a way that is not numbing? Today was Kessenuma near the northern edge of Miyagi Prefecture and Rikuzen-Takata in southern Iwate. Both of these cities were hit very hard with water heights over 5 stories high. As one approaches Kessenuma from inland, it looks very normal. The higher land in the outskirts is filled with shops and cars and people going about their business. The steady stream of military vehicles going in and out is an indication that things are not normal. The western end of the port area wasn’t so badly hit – although boats keep appearing in odd places and many of them are partially blackened by fires. As we head east, the situation quickly deteriorates and the alien landscape of debris, bombed out shells of buildings, and really bad smells come over us. Driving is a challenge. The roadways were the first things to be cleared in the response and they have done a remarkably good job. But the combination of differential settling and subsidence, loss of pavement, piles of debris on either side of the roadways and large vehicles coming the opposite way make it a nail biting experience. And sometimes the road just ends – requiring a long backtrack to get back to firm footing. Megumi has been doing all the driving – thank goodness – and she has done an admirable job. Kessenuma is a major port and the impact to port structures will have economic reverberations for some time. The sunken boats created an oily sheen on the water. This area was knows for fisheries – one fisherman told us he thought it would be ten years before the area returned to normal.
Rikuzen-Takata is the southernmost city in Iwate Prefecture. It sits on a flat plane at end of an elongate bay that appeared to funnel the tsunami three to four miles inland up narrowing river valleys. It made me think of Orick and the mouth of Redwood Creek with about 23,000 more people. The sea walls were obliterated. Wood frame buildings were obliterated. Steel frame buildings were obliterated. The only structures left standing were reinforced concrete, and if you were lucky enough to be in one of those, you needed to be on the fifth floor or higher to survive.
The big question now in cities like Kessenuma and Rikuzen-Takata is how to rebuild. It’s clear from Japanese television that there is pressure from some experts to rebuild the sea walls – just higher and larger. There will certainly be discussions about zoning and land-use planning. There is no easy answer – land is at a premium in Japan and figuring out how to co-exist with the tsunami hazard will be difficult.
Japan Reconnaissance - Day -7
Posted on May 06 2011
May 6, 2011
Disclaimer and Acknowledgements – I should have mentioned this earlier, but better late than never. All the comments in this blog are preliminary and the opinions my own. The purpose of reconnaissance trips is to get a quick overview of the issues in an event and the process begins with small slices of what happened based on what we see, read, and who we talk to. Gradually a picture emerges that (I hope) comes close to the truth. But some of the early hypotheses may turn out to be in error or downright wrong. Numerous Japanese researchers are working on many aspects of the event and other international teams are hear or will be headed to Japan soon. We share our ideas, debate issues, publish results and by a year from now, I expect there will be pretty clear consensus on the most important lessons from this event. But right now, data is still being gathered, and the situation is still fluid. It’s one of the aspects of reconnaissance efforts that I find most stimulating – the scientific process in action and in overdrive. Much of the information I’m passing on here has been gathered by others – in particular, casualty statistics ( National Police Agency), water heights (numerous teams, data compiled by IOC/UNESCO).
A 5.1 aftershock gave us a little rattle around 3:30 AM. Hard to get back to sleep afterwards.
So far we’ve spent most of our time on the broad, flat coastal plain south of Sendai. The tsunami water heights in this area were very large – over 30 feet in some places. This was a big tsunami – the damages impressive and the losses significant. But most concrete buildings in this area appeared to have survived – especially the structures designated as evacuation places. Many of the people we talked to in the shelters had weathered the tsunami in these buildings. Today we headed further north – first to Ishinomaki and then to Minami Sanriku where the waves were higher and the damage more severe.
Ishinomaki, is a port a city of over 160,000 people. Some areas were hit by surges reaching more than 45 feet high. Much of the city was exposed to the tsunami over 5600 died or went missing, the highest overall total of any city in the tsunami area. The reason is most likely exposure – Ishinomaki simply had more people in the area that was flooded. We started in the port area where cleanup had removed almost all traces of major damage in the harbor. Another reminder that reconnaissance teams really need to visit areas early if they are interested in water heights and structural damage. The other side of the city was in much worse shape, but the rate at which debris is being removed is still remarkable. This occurs at both a large and small scale – with massive machines and an army of individual volunteers. It occurred to me as we were walking over piles of discarded tatami mats that this is one industry that should benefit from the tsunami. Perhaps yes – but the benefit is most likely going to be in China as Megumi told me that almost all of Japan’s tatami is now produced overseas.
Last stop of the day was Minami Sanriku, a city noted for its tsunami preparedness efforts including sea walls, tsunami gates to cut off surges at the river mouth, designated evacuation buildings, and a well-exercised disaster prevention organization. The harbor area features a series of commemorative plaques and markers for the past tsunamis to hit the area – 1896 Meiji, 1933 Showa, 1960 Chile. One brightly painted marker clearly shows the 2.6 meter (8 feet) height of the 1960 tsunami. The preparedness efforts would have all worked fine had the tsunami been similar to what happened in those previous events and what the community had planned for. But 2011 easily overtopped and broke the sea walls, and reached fourth floor elevations in much of the city. A particularly tragic story played out at the City’s Disaster Prevention Center, and a designated evacuation place. Keri Luna, a city official kept at the microphone announcing to the public that a tsunami was coming. Until she was finally overwhelmed. Of the thirty people on the fourth floor of the building, only 10 survived. Her body was found only a few days ago. Perhaps the saddest part of the story is that the building is only a five minutes walk from high ground and if everyone had headed to the hill instead of the building, they all would have survived.
Two more aftershocks at the hotel so far this evening….